2018-10-05 | Technical improvements, changes in design, printing- and other errors expected. 29
We recommend you to set the maximal fill level to 90%.
If the current fill level exceeds the maximal fill level, it may cause image disturbances, e.g. mosaic images.
If the net data rate of the signal exceeds the net data rate of the output channel, the modulator overflows. This
overflow leads to disturbances. If the modulator overflows, the status LED on the front side of the device lights
in red.
Filtering the programmes reduces the net data rate of the input signal. Subsequently, the net data rate of the
output signal is also reduced.
The data rate of the DVB-T channel depends furthermore on the chosen channel bandwidth (7 or 8 MHz), on
the set error correction rate (FEC) and the modulation rate (QPSK, QAM16, QAM64) of the modulator.
If the displayed data rate exceeds 90%, there are different possibilities to change it:
Change to a channel with a bandwidth of 8 MHz if a 7 MHz channel was selected previously.
Raise the modulation rate to 64 QAM. QPSK corresponds to the lowest, the QAM64 setting to the highest
output data rate.
Set the forward error correction to 7/8. With this setting, the data rate is increased, but the error
correction is lower. A lower error correction requires a better transmission quality from the antenna
network.
Set the guard interval to 1/32. This shorter guard interval allows you to reach greater data rates.
Reduce the number of selected programmes in the channel list.
COFDM modulated channels allow net data rates from 4.98 up to 31.67 Mbit/s (typically 24).
Modulation Code rate Guard interval
1/4 1/8 1/16 1/32
QPSK 1/2 4.976 5.529 5.855 6.032
2/3 6.635 7.373 7.806 8.043
3/4 7.465 8.294 8.782 9.048
5/6 8.294 9.216 9.758 10.053
7/8 8.709 9.676 10.246 10.556
16-QAM 1/2 9.953 11.059 11.709 12.064
2/3 13.271 14.745 15.612 16.086
3/4 14.929 16.588 17.564 18.096
5/6 16.588 18.431 19.516 20.107
7/8 17.418 19.353 20.491 21.112
64-QAM 1/2 14.929 16.588 17.564 18.096
2/3 19.906 22.118 23.419 24.128
3/4 22.394 24.882 26.346 27.144
5/6 24.882 27.647 29.273 30.16
7/8 26.126 29.029 30.737 31.668
3.6.3. Selected Programmes
The programme table SELECTED PROGRAMS shows the programmes that were activated in phase 2.
To Next Page
Loading...
Need help?
General
